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Nickel‐copper‐zinc (NiCuZn) spinel ferrites have attracted intensive research owing to their unique magnetic properties and low co‐fire temperature. Combustion synthesis has been viewed as a promising protocol for the large‐scale fabrication of NiCuZn spinel ferrites. However, the spinel ferrites prepared by this method usually suffer from limited saturation magnetization and high coercivity due to their large size, which will impose detrimental harmonics on electrical equipment (e. g. transformer, motor, etc.). To address these issues, highly porous NiCuZn spinel ferrite hierarchies were prepared within several hours through a modified solution combustion method, using glucose and ammonium nitrate as the fuel and combustion enhancer, respectively. The as‐obtained NiCuZn spinel ferrite hierarchies show excellent magnetic properties with a high saturation magnetization up to 62.61 emu/g and a low coercivity of 9.6 Oe thanks to the rational distribution of cations and grain size. More importantly, this method also allows various modifications (heteroatom doping) and large‐scale applications, which may be promising for the fabrication of high‐performance soft magnets for electrical equipment. [ABSTRACT FROM AUTHOR]

The gradual depletion of global fossil energy and environmental pollution make the development of hydrogen energy an imminent concern. Two-dimensional g-C3N4 (CN) based heterostructures have attracted considerable research interest in the photocatalytic H2 evolution field, but the unsatisfactory interfacial contact between metal-free CN and other metal oxide/sulfide semiconductors usually results in a low transfer efficiency of charge carriers. Herein, we develop a new homojunction by in situ decoration of CN nanosheets with a C–N compound broken by s-triazine units (abbreviated to BST). The resultant CN/BST homojunction presents significantly enhanced photocatalytic H2 generation (12.47 mmol g−1 h−1), which is about 4 and 33 times higher than that of pristine CN (3.086 mmol g−1 h−1) and BST (0.376 mmol g−1 h−1), respectively. It is revealed that the BST fragments tightly anchored on the CN nanosheets act as electron-trapping agents to rapidly transfer photogenerated electrons from the CN conduction band to generate hydrogen, effectively inhibiting the recombination of photogenerated electrons and holes. The work shows that the construction of a suitable homojunction is an effective way to obtain high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Spinel ferrites have been widely used in various fields, among which nickel‐zinc (NiZn) ferrites have drawn much attention due to their high electrical resistivity as well as low eddy current loss. To accommodate highly‐integrated modern electronic devices, the preparation methods for nano/micro‐sized NiZn ferrites have been widely discussed. Nevertheless, these current synthesis routes are usually cost/time‐consuming, which hinders their large‐scale production for practical applications. Herein, we present a facile, low‐cost synthesis strategy for NiZn ferrites (NixZn1−xFe2O4, x=0, 0.25, 0.5, 0.75 and 1) through a blowing‐combustion method. The effect of Ni/Zn molar concentration on the structure, morphology as well as magnetic properties has been thoroughly investigated through X‐ray diffraction, Raman spectroscopy, scanning electron microscopy and vibrating sample magnetometer. Thanks to the synergetic effect of the pure phase and moderate Ni molar concentration, the Ni0.75Zn0.25Fe2O4 shows an enhanced saturation magnetization of 44.98 emu/g. More importantly, this blowing‐combustion method may also be commonly applied to other spinel ferrites with different stoichiometric ratios and heteroatom doping. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon materials have shown great potential for electrochemical energy storage application due to their natural abundance, high porosity, and hierarchical structure. Herein, we report the fabrication of tubular catkin-derived carbon microtubes (denote as CMTs) by directly annealing catkin in Ar, and study the effect of activation on their physicochemical characteristics as well as their lithium storage performance/behavior. The activated CMTs (a-CMTs), which are obtained by annealing pristine CMTs (p-CMTs) (436 m2 g−1, 0.109 cc g−1) with KOH as the activating agent, display a porous structure with a high specific area (1048 m2 g−1) and large pore volume (0.751 cc g−1). When examined as anode materials for lithium-ion batteries, both p-CMTs and a-CMTs show excellent cycling and rate performance, delivering reversible capacities of 397 and 493 mA h g−1 after 400 cycles at 100 mA g−1, respectively, which correspondingly show pseudocapacitive and diffusion-controlled lithium storage behaviors. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) has been considered as a promising anode material for sodium‐ion batteries (SIBs), because of its abundance, safety and eco‐friendliness. However, the inferior electronic conductivity and low sodium ion diffusion rate of TiO2 hinder its improvement of electrochemical performance. To overcome these drawbacks, herein, core‐shell Se‐doped TiO2@carbon nanotubes (denoted as Se‐TiO2@CNTs) are successfully designed and fabricated, in which the TiO2 nanoparticle aggregated shells are conformally coated on the carbon nanotubes, while the metallic Se species are physically confined within the meso/micropores. When examined as a SIB anode, the Se‐TiO2@CNTs electrode demonstrates excellent sodium storage performance, correspondingly delivering high reversible capacities of 222.7/208.5 mA h g−1 after 200/1000 cycles at current densities of 0.2/1.0 A g−1, and even a capacity of 140.2 mA h g−1 after 4500 cycles at a high‐rate of 5.0 A g−1. The high reversible capacity, long‐term cycling stability, and high‐rate capability of the Se‐TiO2@CNTs can be owing to the unique structure characteristics, as the hollow/porous structure with high specific surface area of 335.4 m2 g−1 efficiently shortens the Na+ diffusion length and facilitates the electrolyte penetration, while Se‐doping and carbon supporting greatly enhance the electronic conductivity of the Se‐TiO2@CNTs electrode. [ABSTRACT FROM AUTHOR]

Transition metal phosphides are emerging as potential anode materials for lithium‐ion batteries (LIBs) due to their high theoretical capacity and good thermal stability, but the severe volume changes during the charge/discharge process and low electrical conductivity have hampered their practical application. Herein, the facile synthesis of carbon‐coated CoP nanoparticles (CoP@C) with uniform spherical morphology is demonstrated through the solvothermal method followed by annealing and phosphating treatments, in which an interesting precursor, the Co–gluconate complex, is prepared as the Co/C sources. When used as the LIB anode, the CoP@C electrode displays excellent cycling stability with a reversible capacity of 483.4 mA h g−1 upon 1000 cycles at 0.5 A g−1. The superior lithium storage performance is attributed to the unique composite structure of CoP@C with the nanosized CoP particles wrapped into the carbon matrices, which can enhance the electrical conductivity, provide sufficient reaction sites, shorten the Li+ transport path, and buffer the volume changes of the electrode upon lithiation/delithiation. More importantly, the strategy of generating gluconate–metal complex as the metal‐ and carbon‐containing precursor can be widely applied in the synthesis of various functional materials for energy‐related applications. [ABSTRACT FROM AUTHOR]

Conversion‐type transition metal oxide MoO3 has attracted considerable interest as a promising anode material for lithium ion batteries (LIBs), but it suffers from the low electronic conductivity and the large volume changes upon lithiation/delithiation. To overcome these drawbacks, we herein report the full encapsulation of core‐shelled MoO3‐TiO2 into the carbon nanofibers (CNFs) via a facile coaxial electrospinning followed by a two‐step annealing process. TiO2 shells and MoO3 cores were coaxially integrated into the porous CNFs (denote the composite as TiO2/MoO3@CNFs). The two‐step annealing strategy (carbonization in Ar and then oxidization in air) allows the readily encapsulation of MoO3 into CNFs. When applied as anode materials for LIBs, the coaxial TiO2/MoO3@CNFs demonstrate superior lithium storage performance, delivering a high reversible capacity of 561 mAh/g after 300 cycles at 1000 mA/g with a much higher capacity retention of 70.8% than that of the MoO3@CNFs without TiO2 layers (only 42.3%). The results clearly demonstrate that the CNFs matrices and the TiO2 shells together efficiently enhance the electrode conductivity and buffer the volume changes of MoO3 upon cycling. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) is a promising anode for lithium‐ion batteries (LIBs) due to its long lifespan and high rate capability, arising from its excellent structural stability upon lithium intercalation‐deintercalation, but suffers from low conductivity and diffusivity. In contrast, germanium (Ge) possesses high specific theoretical capacity (1600 mA h g−1) as well as high electrical conductivity and high Li+ diffusivity, but the large volume changes upon cycling and the high price still impede its practical application. Herein, with the objective to overcome the drawbacks of TiO2‐based anode materials, Ge/TiO2@C nanotablets with a small amount of Ge content are successfully prepared by annealing C4H12GeO4/MIL‐125 mixtures in Ar/H2 atmosphere. Benefiting from the well‐dispersion of Ge nanoparticles within the TiO2@C matrices, the composites exhibit superior electrochemical performance when examined as a LIB anode material, delivering high reversible capacities of 502/258 mA h g−1 after 200/500 cycles at current densities of 200/500 mA g−1, respectively. Notably, the Ge/TiO2@C shows enhanced surface/pore features and demonstrates improved conductivity, lithium diffusion and specific capacities, owing to the introduction of Ge component. [ABSTRACT FROM AUTHOR]

In order to overcome the poor electrical conductivity of titania (TiO2) and silica (SiO2) anode materials for lithium ion batteries (LIBs), we herein report a facile preparation of integrated titania–silica–carbon (TSC) nanofibers via electrospinning and subsequent heat-treatment. Both titania and silica are successfully embedded into the conductive N-doped carbon nanofibers, and they synergistically reinforce the overall strength of the TSC nanofibers after annealing (Note that titania–carbon or silica–carbon nanofibers cannot be obtained under the same condition). When applied as an anode for LIBs, the TSC nanofiber electrode shows superior cycle stability (502 mAh/g at 100 mA/g after 300 cycles) and high rate capability (572, 518, 421, 334, and 232 mAh/g each after 10 cycles at 100, 200, 500, 1000 and 2000 mA/g, respectively). Our results demonstrate that integration of titania/silica into N-doped carbon nanofibers greatly enhances the electrode conductivity and the overall structural stability of the TSC nanofibers upon repeated lithiation/delithiation cycling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nickel-copper-zinc (NiCuZn) ferrites were prepared by a facile blowing-combustion method. • Variation of zinc content with temperature was investigated through inductive coupled plasma (ICP). • The effect of sintering temperatures on structural and magnetic properties of NiCuZn ferrites were investigated. We report the fabrication of nickel-copper-zinc (NiCuZn) ferrites via a facile blowing-combustion method, where the grain size and morphology can be readily controlled by adjusting the sintering temperature. The effect of sintering temperatures on the structural evolution as well as the magnetic properties of the NiCuZn ferrites was systematically studied. It's found that the Zn elemental content is highly dependent on the sintering temperature and would undergo evaporation when annealing at 800 °C, which consequently greatly affects the magnetic properties of NiCuZn ferrites. [ABSTRACT FROM AUTHOR]